bundle: extract the parsing of the bundle type in a function We are going to introduce significant extensions of the bundle parsing code to support creation of bundle2 through the bundle command. As an early step, we extract the logic in its own function.

changegroup: add version argument to getchangegroup For some obscure reasons (probably upsetting a Greek goddess), getchangegroup did not had a 'version' argument to control the changegroup version. We fixes this to allow cg02 to be used with 'hg bundle' in the future.

changegroup: add version argument to getlocalchangegroup For some obscure reasons (probably upsetting a Greek goddess), getlocalchangegroup did not have a 'version' argument to control the changegroup version. We fix this to allow cg02 to be used with 'hg bundle' in the future.

shelve: bundle using bundle2 if repository is general delta (issue4862) This will prevent expensive delta computation on bundling and is similar to what we do for strip backup.